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Azure relay

Create envelopes and send secure messages from a no-code tool, with plain HTTP calls.

The relay is an Azure Functions application that you deploy in your own Azure subscription. It exposes three HTTP addresses, protected by a key, and calls Secure Exchanges with the SDK and your licence credentials, kept in your Function App's configuration.

Route Role
POST /api/enveloppe Creates an envelope link: your recipient sends documents back to you.
POST /api/message Sends a secure message to one or more recipients.
GET /api/version Gives the installed version, and whether an update exists.

Any tool that can send a JSON POST request can call it: Zapier, Make, Power Automate, a webhook, a script. See Relay API.

Data path

  • The content of a message travels in plain text through the tool that calls the relay, then through your Function App. The relay encrypts it, with the SDK, before sending it to Secure Exchanges. Choose a tool, and a configuration of that tool, that does not keep request bodies longer than necessary.
  • The links, passwords and opening codes returned by the relay remain in the calling tool's history.
  • Your licence credentials remain in your Function App's configuration. They are never sent to the tool that calls the relay.

Limits

  • No attachments: the /api/message route does not send files. Write to supportdev@secure-exchanges.info if you need them.
  • An envelope targets a single recipient, and the relay does not send it to them: you send them the link.
  • No tracking or deletion route.
  • No limit on the number of calls: anyone who has the key can consume your licence. See Configure and secure.

What the deployment creates

Resource Characteristics
Storage account Standard LRS, HTTPS only, TLS 1.2 minimum, public blob access disabled, with a private app-package container
Flex Consumption plan Linux, billed by usage
Function App .NET 8 isolated process, system-assigned managed identity, HTTPS only, TLS 1.2 minimum, FTPS disabled

The deployment creates no Application Insights resource.

Costs

Three items, all billed by usage:

Item What is billed
Function App (Flex Consumption) Execution time, in GB-seconds, and the number of executions
Storage account The relay package and its metadata, a few megabytes
Network egress Calls to Secure Exchanges, a few kilobytes per call

To estimate your volume: at 512 MB per instance, the default value, a call that lasts one to three seconds represents 0.5 to 1.5 GB-seconds. For 1,000 calls a month, count 500 to 1,500 GB-seconds and 1,000 executions. Enter these values in the Azure pricing calculator, for Azure Functions on the Flex Consumption plan: prices vary by region, and Microsoft applies a monthly free grant whose amount changes.

With the Azure Key Vault option, add the vault read operations. Increasing the memory per instance, or turning on always-ready instances (which the template leaves off), increases the bill.

Where to start

  1. Deploy
  2. Configure and secure
  3. Use with a no-code tool